Energy-efficient liquid-cooled battery thermal management using interconnected wavy minichannel cold plates

This study investigates the design and optimisation of a liquid-cooled battery thermal management system for prismatic lithium-ion phosphate batteries operating under elevated ambient temperatures (45 °C). A novel interconnected wavy minichannel cold plate (MCP) is proposed and systematically evaluated against three designs, namely sinusoidal–wavy, modified wavy, and periodic converging–diverging minichannels, with emphasis on coupled thermal and hydraulic performance. A transient conjugate heat transfer model is developed for a 45 Ah prismatic cell discharged at a 3C rate and validated against published data. The analysis is extended to three battery module configurations comprising 4, 5, and 6 cells to assess scalability and architectural effects. Thermal performance is assessed using dual criteria: maintaining a maximum temperature around 45 °C and limiting the temperature gradient within the cell to around 10 °C. The results demonstrate that the interconnected wavy MCP significantly enhances heat transfer via inducing secondary flow structures while incurring minimal pressure drop penalties, thereby outperforming other benchmark designs. Module-level analysis, extrapolated to a 60-cell battery pack, reveals that higher coolant (water) inlet temperatures, despite requiring increased flow velocities, substantially reduce total energy consumption by lowering the primary cooling load. Among the configurations studied, the six-cell module operating at inlet temperatures of 30 °C and 35 °C achieves the most favourable balance between thermal safety and energy efficiency, facilitated by a reduced number of plates (20 per pack). These findings provide critical insights for developing a compact, energy-efficient management system for electric vehicles operating in hot climates, highlighting the importance of integrated thermal–hydraulic design and system-level energy analysis for practical implementation.